The Construction of the Pentagon

The construction of the Pentagon began, eerily enough, on September 11, 1941. To mark the 70th anniversary of the groundbreaking—and the 10th anniversary of the 9/11 attacks—LIFE.com is featuring a gallery of previously unpublished photos of the construction process.

Photo: Thomas D. McAvoy/TIME & LIFE Pictures

Photo: Myron Davis/TIME & LIFE Pictures

From LIFE (December 1942):
Both employees and visitors "resent the eight and two-fifths miles of barren corridors, the jammed ramps, the pile-up at entrances and exits, the parking and transportation problems, the six overcrowded cafeterias, the staggered working hours."

Also on Mental Floss:

DID YOU KNOW? Marlon Brando hated memorizing lines so much that he posted cue cards everywhere to help him get through scenes.
He even asked for lines to be written on an actress's posterior. (That request was denied.)